Hormones and the auditory system: A review of physiology and pathophysiology

Asynchronous development of the mouse auditory cortex is driven by hemispheric identity and sex

Lateralized auditory processing is essential for specialized functions such as speech processing, typically dominated by the Left Auditory Cortex (ACx) in humans. Hemispheric specializations also occur in the adult mouse ACx, but their developmental origins are unclear. Our study finds that the Left and Right ACx in mice reach developmental milestones at different ages. Thalamocortical responses and maturation of synaptic dynamics develop earlier in the Right ACx than the Left. We show that this timing offset predicts hemisphere-dependent differences in sensory-driven plasticity. Juvenile tone exposure at specific times results in imbalanced adult tone frequency representations in the Right and Left ACx. Additionally, sex influences the timing of plasticity; female Right ACx plasticity occurs before male Right ACx, and female Left ACx aligns with male Right ACx plasticity. Our findings demonstrate that sex and hemispheric identity drive asynchronous development and contribute to functional differences in sensory cortices.

Noise annoyance due to different sources is associated with tinnitus presence and distress in the general population

BACKGROUND

The pathophysiology of tinnitus is not yet fully understood. Although there is a large amount of evidence associating traffic noise exposure with non-auditory health outcomes, there is no evidence regarding the impact of noise annoyance on auditory disorders such as tinnitus.

OBJECTIVE

Thus, we aimed to investigate the association between noise annoyance due to different sources and tinnitus presence and distress in the general population.

METHODS

Data of 6813 participants from a large German population-based cohort were used (Gutenberg Health Study). Participants were asked about the presence of tinnitus and how much they were bothered by it. In addition, information on annoyance from road traffic, aircraft, railways, industrial, and neighborhood noise during the day and sleep was collected through validated questionnaires.

RESULTS

The prevalence of tinnitus was 27.3%, and the predominant sources of noise annoyance in these subjects were aircraft, neighborhood, and road traffic noise. Overall, logistic regression results demonstrated consistent positive associations between annoyance due to different noise sources and prevalent risk of tinnitus with increases in odds ratios ranging from 4 to 11% after adjustment for sex, age, and socioeconomic status. Likewise, consistent increases in odds ratios were observed for tinnitus distress in subjects with prevalent tinnitus. For instance, neighborhood noise annoyance during the sleep was associated with a 26% increase in tinnitus distress (OR 1.26, 95% CI 1.13; 1.39).

IMPACT

This is the first study investigating the association between noise annoyance and tinnitus presence and distress in a large cohort of the general population. Our results indicate consistent and positive associations between various sources of noise annoyance and tinnitus. These unprecedented findings are highly relevant as noise annoyance and tinnitus are widespread. The precise etiology and locus of tinnitus remain unknown, but excessive noise exposure is thought to be among the major causes. This study suggests that transportation and neighborhood noise levels thought merely to contribute to annoyance and non-auditory health effects may be sufficient to cause or exacerbate tinnitus.

Evaluation of Changes in the Patency of the Nasal Cavity and Eustachian Tube Depending on the Phase of the Menstrual Cycle: A Pilot Study

(1) Background: Estrogen and progesterone, hormones specific to females, undergo fluctuations during the menstrual cycle. The aim of this study was to assess subjective and objective changes in nasal cavity and Eustachian tube patency depending on the phase of the menstrual cycle in two groups of women: those in a follicular phase group and those in a luteal phase group. (2) Materials and Methods: The study group consisted of 25 healthy non-pregnant women aged 24 to 32. Based on the phase of the cycle confirmed in sonography, they were divided into follicular phase (FP) and luteal phase (LP) groups. The Eustachian tube and nasal cavity patency examination was carried out using a SNOT-22 Questionnaire, a rhinomanometer, and a tympanometer. (3) Results: We observed that the incidence of nasal obstruction in SNOT-22 was significantly dependent on the cycle phase (p = 0.012) and was lower in the FP compared to the LP. Similar relationships were noticed between the cycle phase and the rhinomanometry outcome, where the LP was associated with a lower flow. We also revealed that the incidence of ear blockage significantly depended on the cycle phase (p = 0.001) and was lower in the FP compared to the LP. Women whose nasal patency deteriorated during the LP also had more negative pressure values in tympanometry. We observed that patients with negative PEAK L and R levels had a lower flow in rhinomanometry. (4) Conclusions: The results highlight the menstrual cycle's substantial impact on both subjective and objective nasal and Eustachian tube patency measurements. The novel finding in this study is that women whose nasal patency deteriorated during the luteal phase also had more negative pressure values in tympanometry. These results suggest that the deterioration of hearing during the menstrual cycle could be a result of swelling of the nasal mucosa and tubes.

Comparative Efficacy of Different Therapeutic Interventions in Eustachian Tube Dysfunctions: A Cross-Sectional Analysis

Eustachian tube dysfunction (ETD) affects a significant portion of the population, manifesting symptoms that impact the quality of life. Despite the prevalence of ETD, there remains a notable gap in comprehensive studies exploring the condition's dynamics within specific demographic contexts, particularly within Saudi Arabia. This study aimed to assess the prevalence and severity of ETD across different demographic groups, to evaluate the efficacy of various treatment modalities, and to identify key predictors of treatment response in a Saudi Arabian cohort. A cross-sectional study was conducted from June 2022 to May 2023 in tertiary care hospitals in the Aseer region, Saudi Arabia. Participants included adults diagnosed with ETD, assessed through clinical symptoms, otoscopic examinations, audiometric evaluations, tympanometry, and the ETDQ-7 questionnaire. The study incorporated advanced diagnostics such as nasopharyngoscopy and pressure equalization tube function tests and involved 154 participants, revealing significant variations in ETD severity, with the 46-60 age group exhibiting the highest mean ETDQ-7 score of 4.85, and urban residents displaying lower severity scores compared to rural counterparts. Pharmacological interventions were most effective, achieving the highest symptom relief and audiological improvement rates of 87.78%. Multivariate regression highlighted age, geographic location, and treatment modality as key predictors of treatment efficacy, with notable interaction effects between climate conditions and treatment types influencing outcomes. The findings underscore the heterogeneity in ETD presentation and the differential efficacy of treatment modalities.

Health position paper and redox perspectives - Disease burden by transportation noise

Transportation noise is a ubiquitous urban exposure. In 2018, the World Health Organization concluded that chronic exposure to road traffic noise is a risk factor for ischemic heart disease. In contrast, they concluded that the quality of evidence for a link to other diseases was very low to moderate. Since then, several studies on the impact of noise on various diseases have been published. Also, studies investigating the mechanistic pathways underlying noise-induced health effects are emerging. We review the current evidence regarding effects of noise on health and the related disease-mechanisms. Several high-quality cohort studies consistently found road traffic noise to be associated with a higher risk of ischemic heart disease, heart failure, diabetes, and all-cause mortality. Furthermore, recent studies have indicated that road traffic and railway noise may increase the risk of diseases not commonly investigated in an environmental noise context, including breast cancer, dementia, and tinnitus. The harmful effects of noise are related to activation of a physiological stress response and nighttime sleep disturbance. Oxidative stress and inflammation downstream of stress hormone signaling and dysregulated circadian rhythms are identified as major disease-relevant pathomechanistic drivers. We discuss the role of reactive oxygen species and present results from antioxidant interventions. Lastly, we provide an overview of oxidative stress markers and adverse redox processes reported for noise-exposed animals and humans. This position paper summarizes all available epidemiological, clinical, and preclinical evidence of transportation noise as an important environmental risk factor for public health and discusses its implications on the population level.

The fudan tinnitus relieving system application for tinnitus management

OBJECTIVE

Tinnitus is a highly prevalent hearing disorder, and the burden of tinnitus diagnosis and treatment is very heavy, especially in China. In order to better benefit the majority of tinnitus patients, we developed a new mobile app based on our patented invention - named the Fudan Tinnitus Relieving System (FTRS) - for tinnitus management. The FTRS app aims to alleviate patients' tinnitus symptoms using customized sound therapy, to evaluate the treatment effect, to provide a doctor-patient communication platform, and to support tinnitus rehabilitation and auditory health.

METHODS

In this study, we introduced the major functions of the FTRS app, analyzed the geographical distribution of users around China, and performed an analysis on the demographic and clinical characteristics of patients with tinnitus, including age and tinnitus position, duration, frequency, and severity in both men and women based on the user information collected by the FTRS. The data for 22,867 participants (males: 13,715; females: 9,152) were included in the statistical analysis.

RESULTS

The FTRS app has been popular with tinnitus patients since its launch in May 2018 with its integrated pitch-matching test, individualized sound therapy, follow-up assessment, and provision of easy-to-understand science and education for tinnitus. The users were located throughout Mainland China but primarily concentrated in Shanghai, Jiangsu, Zhejiang, Guangdong, and Shandong provinces. We observed gender differences regarding age and tinnitus frequency, severity, and position among the app's users. The FTRS has not only facilitated patients' access to treatment at times and places that are convenient for them, but also provides a large amount of data based on user feedback in order to support clinical tinnitus research.

CONCLUSIONS

Compared with traditional face-to-face medical treatment, the FTRS greatly reduced medical costs and enabled patients with tinnitus to arrange their own treatment times. At the same time, the FTRS has provided standardized tinnitus data that have laid a foundation for clinical research on tinnitus. However, because of differences in the popularity and utilization of smart devices, FTRS user data might only reflect the situation of tinnitus patients who can effectively use smart devices. Therefore, the findings of this study need to be interpreted with caution.

Sex differences and the effect of female sex hormones on auditory function: a systematic review

Aims

First, to discuss sex differences in auditory function between women and men, and whether cyclic fluctuations in levels of female sex hormones (i.e., estradiol and progesterone) affect auditory function in pre-menopausal and post-menopausal women. Second, to systematically review the literature concerning the discussed patterns in order to give an overview of the methodologies used in research. Last, to identify the gap in knowledge and to make recommendations for future work.

Methods for the systematic review

Population, Exposure, Control, Outcome and Study design (PECOS) criteria were used in developing the review questions. The review protocol follows the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and was pre-registered in the Prospective Register of Systematic Reviews (PROSPERO; CRD42020201480). Data Sources: EMBASE, PubMed, MEDLINE (Ovid), PsycINFO, ComDisDome, CINAHL, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL) via Cochrane Library, and scanning reference lists of relevant studies, and internet resources (i.e., Mendeley) were used. Only studies published between 1999 and 2022, in English, or in English translation, were included. The quality of evidence was assessed using the Newcastle-Ottawa Scale (NOS).

Results

Sex differences: Women had more sensitive hearing (measured at the level of peripheral and central auditory system) than men. Cyclic fluctuations: Auditory function in women fluctuated during the menstrual cycle, while no such fluctuations in men over the same time period were reported. Hearing sensitivity improved in women during the late follicular phase, and decrease during the luteal phase, implying an effect of female sex hormones, although the specific effects of estradiol and progesterone fluctuations on the central auditory system remain unclear. Hearing sensitivity in women declined rapidly at the onset of menopause.

Conclusion

The review has shown the following. Consistent sex differences exist in auditory function across the auditory pathway with pre-menopausal women often showing better function than age-matched men. Moreover, pre-menopausal women show fluctuations in hearing function across the menstrual cycle with a better function during the peak of estradiol or when the ratio of estradiol to progesterone is high. Third, menopause marks the onset of hearing loss in women, characterized by a rapid decline in hearing sensitivity and a more pronounced loss than in age-matched men. Finally, the systematic review highlights the need for well-designed and -controlled studies to evaluate the influence of estradiol and progesterone on hearing by consistently including control groups (e.g., age-matched man), using objective tests to measure hormonal levels (e.g., in saliva or blood), and by testing participants at different points across the menstrual cycle.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020201480, identifier CRD42020201480.

Transportation Noise and Risk of Tinnitus: A Nationwide Cohort Study from Denmark

BACKGROUND

There is a growing body of evidence linking residential exposure to transportation noise with several nonauditory health outcomes. However, auditory outcomes, such as tinnitus, are virtually unexplored.

OBJECTIVES

We aimed to investigate the association between residential transportation noise and risk of incident tinnitus.

METHODS

We conducted a nationwide cohort study including all residents in Denmark age ≥30y, of whom 40,692 were diagnosed with tinnitus. We modeled road traffic and railway noise at the most (Ldenmax) and least (Ldenmin) exposed façades of all Danish addresses from 1990 until 2017. For all participants, we calculated 1-, 5-, and 10-y time-weighted mean noise exposure and retrieved detailed information on individual- and area-level socioeconomic covariates. We conducted analyses using Cox proportional hazards models.

RESULTS

We found positive associations between exposure to road traffic noise and risk of tinnitus, with hazard ratios of 1.06 [95% confidence interval (CI): 1.04, 1.08] and 1.02 (95% CI: 1.01, 1.03) per 10-dB increase in 10-y Ldenmin and Ldenmax, respectively. Highest risk estimates were found for women, people without a hearing loss, people with high education and income, and people who had never been in a blue-collar job. The association with road Ldenmin followed a positive, monotonic exposure-response relationship. We found no association between railway noise and tinnitus.

DISCUSSION

To our knowledge, this is the first study to show that residential exposure to road traffic noise may increase risk of tinnitus, suggesting noise may negatively affect the auditory system. If confirmed, this finding adds to the growing evidence of road traffic noise as a harmful pollutant with a substantial health burden. https://doi.org/10.1289/EHP11248.

The association between stress, emotional states, and tinnitus: a mini-review

Extensive literature supporting the view of tinnitus induced stress in patients is available. However, limited evidence has been produced studying the opposite, that is, does stress cause tinnitus? The hypothalamus pituitary adrenal axis, one of the main neuroendocrine systems involved in stress response, is commonly disturbed in tinnitus patients. Patients with chronic tinnitus have been shown to develop abnormal responses to psycho-social stress, where the hypothalamus pituitary adrenal axis response is weaker and delayed, suggesting chronic stress contributes to the development of chronic tinnitus. The sympathetic branch of the autonomic nervous system also plays a major role in stress response and its chronic hyperactivity seems to be involved in developing tinnitus. Psycho-social stress has been shown to share the same probability of developing tinnitus as occupational noise and contributes to worsening tinnitus. Additionally, exposure to high stress levels and occupational noise doubles the likelihood of developing tinnitus. Interestingly, short-term stress has been shown to protect the cochlea in animals, but chronic stress exposure has negative consequences. Emotional stress also worsens pre-existing tinnitus and is identified as an important indicator of tinnitus severity. Although there is limited body of literature, stress does seem to play a vital role in the development of tinnitus. This review aims to highlight the association between stress, emotional states, and the development of tinnitus while also addressing the neural and hormonal pathways involved.

From menarche to menopause, heavy menstrual bleeding is the underrated compass in reproductive health

Menstruation is defined as monthly uterine bleeding, regarded as a sign of reproductive health. When characterized by excessive bleeding (heavy menstrual bleeding [HMB]), it may act as a useful clinical marker for diagnosis of reproductive diseases. Endometrial and myometrial mechanisms underlying abnormal uterine bleeding (AUB), which includes HMB, have hormonal, cellular, and molecular aspects. Structural and nonstructural causes of AUB, presenting with HMB as the major symptom, result in iron depletion and consequent anemia. Heavy menstrual bleeding can be considered as a single entity to identify the possible underlying causes, which may be different to some extent to those of AUB, as a whole. Furthermore, the difficulties in defining HMB through objective methods do not allow the current epidemiological scenario on the prevalence of the symptom among reproductive-age women to be outlined. Moreover, the introduction of new diagnostic methods, including imaging technologies, entails a revision of the available figures on HMB in different age groups from menarche to menopause. In addition, a proper diagnostic algorithm for HMB should be implemented to adapt recommendations for clinical investigation when HMB is present.

Effect of diurnal changes on dichotic listening in younger adults with normal hearing

Background

Diurnal changes can be defined as the time of the day over an individual's performance level for different activities that involve physical and mental tasks.

Objective

The current study aimed to evaluate the effect of diurnal changes in scores obtained for the Dichotic Consonant-Vowel paradigm by young adults with normal hearing sensitivity.

Method

Based on the ‘Morningness-Eveningness questionnaire’ given by Horne & Ostberg, the subjects were divided into moderately-morning, intermediate and moderately-evening categories. The Dichotic Consonant-Vowel tests were performed during morning and evening, and the right ear, left ear and double correct scores were compared between morning and evening for each category.

Results

There was significant diurnal changes noted for moderately morning and evening categories, where morning-type individuals performed better during morning and evening-type individuals performed better during the evening. The scores of intermediate individuals remained unchanged between morning and evening test results.

Conclusion

Diurnal change is a phenomenon associated with an individual's biological clock mechanism. Hence, attention and inhibitory controls aid them in carrying out tasks that require sufficient physical and mental efforts. The current study suggests that clinicians and researchers consider diurnal changes as an extraneous variable that could affect the reliability of the Dichotic Consonant-Vowel test results.

Genetic Association of rs1021188 and DNA Methylation Signatures of TNFSF11 in the Risk of Conductive Hearing Loss

Otosclerosis (OTSC) is a complex bone disorder of the otic capsule, which causes conductive hearing impairment in human adults. The dysregulation of the signaling axis mediated by the receptor activator of nuclear factor-kappa-B (RANK), RANK ligand (RANKL), and osteoprotegerin has been widely attributed to the context of metabolic bone disorders. While genetic associations and epigenetic alterations in the TNFSF11 gene (RANKL) have been well-linked to metabolic bone diseases of the skeleton, particularly osteoporosis, they have never been addressed in OTSC. This study aimed to assess whether the genetic association of rs1021188 polymorphism in the upstream of TNFSF11 and the DNA methylation changes in its promoter CpG-region reveal the susceptibility of OTSC. Peripheral blood DNA samples were collected from unrelated Tunisian-North African subjects for genotyping (109 cases and 120 controls) and for DNA methylation analysis (40 cases and 40 controls). The gender-stratified analysis showed that the TNFSF11 rs1021188 C/T was associated with OTSC in men (p = 0.023), but not in women (p = 0.458). Individuals with CC genotype were more susceptible to OTSC, suggesting an increased risk to disease development. Using publicly available data, the rs1021188 was within a cluster grouping the subpopulations with African ethnicity. Moreover, 26 loci in the TNFSF11 gene were in linkage disequilibrium with rs1021188, revealing relative similarities between different populations. Significant differences in both DNA methylation and unmethylation status were detected with 4.53- and 4.83-fold decreases in the global DNA methylation levels in female and male OTSC groups, respectively. These changes could contribute to an increased risk of OTSC development. Bioinformatic analyses indicated that each of the rs1021188 variations and the DNA methylation changes in the promoter CpG-sites within TNFSF11 may play an important role in its transcription regulation. To our knowledge, this is the first study that investigates an independent effect of the rs1021188 polymorphism and DNA hypomethylation of TNFSF11 promoter in OTSC. Genetic and epigenetic changes in the regulatory regions of TNFSF11 could offer new molecular insights into the understanding of the complexity of OTSC.

Effects of hormone therapy containing 2 mg drospirenone and 1 mg 17β-estradiol on postmenopausal exacerbation of Meniere's disease: Preliminary study

The present study aimed to evaluate the effects of 2 mg drospirenone (DRSP) and 1 mg 17β-estradiol (E2) hormone therapy (HT) in combination with rehabilitation therapy for postmenopausal women with Meniere's disease (MD). The combined drug hormone treatment was denoted as DRSP/E2. A total of 65 postmenopausal female patients with MD and severe distress were enrolled in the present prospective study. A total of 31 women comprised the study group (group A), undergoing HT and rehabilitation therapy, whereas 34 women who opted for rehabilitation therapy alone comprised the control group (group B). Vestibular function and distress associated with MD were assessed by stabilometry and the Dizziness Handicap Inventory (DHI) questionnaire, respectively. The data were collected at baseline and during the 3- and 6-month follow-up visits. The areas of the stabilometric ellipses exhibited a higher reduction in group A compared with group B with regard to the baseline values at both follow-up assessments (P<0.001). At baseline, both groups exhibited severe self-perceived discomfort, with similar DHI scores of 72.3±3.7 (group A) and 70.6±3.9 (group B; P=0.07). At the 3-month follow-up, both groups underwent a gradual improvement, which was significantly higher in group A (47.5±3.7) compared with in group B (64.2±3.3; P<0.001). At the 6-month follow-up, the DHI scores were improved in group A (43.4±3.4) compared with in group B (58.5±3.1; P<0.001). Therefore, DRSP/E2 HT was effective in reducing the fluid overload, which is characteristic of MD. The findings of the present study demonstrated that integrated therapy based on the administration of DRSP/E2 HT and rehabilitation may be more effective compared with rehabilitation alone for the management of postmenopausal exacerbation of MD.

Risk factors associated with idiopathic sudden sensorineural hearing loss in pregnant South Korean women: a nationwide population-based study

OBJECTIVE

Sudden sensorineural hearing loss (SSNHL) is rare in pregnancy and can be attributed to pregnancy-induced changes in hormone levels that increase thrombogenic risk and alter cochlear microcirculation with consequent development of sudden deafness. The study aimed to analyze the risk factors associated with SSNHL in pregnant South Korean.

METHODS

A retrospective study of the incidence and risk factors associated with SSNHL before pregnancy enrolled 401,470 Korean women who delivered between January 2010 and December 2014. All participants underwent a pre-pregnancy national health screening examination through the National Health Insurance Corporation. We investigated the risk factors in 459 pregnant women with sudden sensorineural hearing loss and in 401,011 pregnant women without SSNHL through the pre-pregnancy national health screening examination and adverse perinatal outcome.

RESULTS

No statistically significant intergroup differences were observed in the maternal age, parity, method of delivery, gestational age at delivery, body mass index, blood pressure, as well as fasting blood glucose and cholesterol levels. After adjusting for maternal age, the pre-pregnancy body mass index was associated with an increased risk of sensorineural hearing loss in pregnancy (adjusted odds ratio 1.52, 95% confidence interval 1.04-2.22). The sensorineural hearing loss did not increase the risk for gestational hypertension, preterm birth (<37 weeks' gestation), small- and large-for-gestational-age infants, postpartum hemorrhage, placenta previa, and placental abruption.

CONCLUSION

SSNHL can occur throughout pregnancy and is associated with maternal pre-pregnancy obesity. Notably, it does not increase risks during delivery or cause adverse perinatal outcomes.

Evidence of Tinnitus Development Due to Stress: An Experimental Study in Rats

OBJECTIVES/HYPOTHESIS

Tinnitus can develop due to, or be aggravated by, stress in a rat model. To investigate stress as a possible causal factor in the development of tinnitus, we designed an animal study that included tinnitus behavior and excitatory/inhibitory neurotransmitter expression after noise exposure as well as restraint stress.

STUDY DESIGN

An experimental animal study.

METHODS

Wistar rats were grouped according to single or double exposure to noise and restraint stress. The noise exposure (NE) group was subjected to 110 dB sound pressure level (SPL) of 16 kHz narrow-band noise (NBN) for 1 hour, and the restraint stress (RS) group was restrained for 1 hour with or without noise exposure. Gap prepulse inhibition of the acoustic startle (GPIAS) reflex was measured at an NBN of 16 kHz to investigate tinnitus development. Various immunohistopathologic and molecular biologic studies were undertaken to evaluate possible mechanisms of tinnitus development after noise and/or restraint stress.

RESULTS

The RS-only group showed a reduced GPIAS response, which is a reliable sign of tinnitus development. In the double-stimulus groups, more tinnitus-development signs of reduced GPIAS responses were observed. The expression of γ-aminobutyric acid A receptor α1 (GABAAR α1) in the hippocampus decreased in the NE│RS group. Increased N-methyl-d-aspartate receptor1 intensities in the NE│RS group and decreased GABAAR α1 intensities in the RS and NE│RS groups were observed in the CA3 region of the hippocampus.

CONCLUSIONS

Tinnitus appeared to develop after stress alone in this animal study. An imbalance in excitatory and inhibitory neurotransmitters in the hippocampus may be related to the development of tinnitus after acute NE and/or stress.

LEVEL OF EVIDENCE

NA Laryngoscope, 2021.

Reproductive- and Social-State Plasticity of Multiple Sensory Systems in a Cichlid Fish

Intra- and inter-sexual communications are vital to the survival and reproductive success of animals. In species that cycle in and out of breeding or other physiological condition, sensory function can be modulated to optimize communication at crucial times. Little is known, however, about how widespread this sensory plasticity is across taxa, whether it occurs in multiple senses or both sexes within a species, and what potential modulatory substances and substrates are involved. Thus, studying modulation of sensory communication in a single species can provide valuable insights for understanding how sensory abilities can be altered to optimize detection of salient signals in different sensory channels and social contexts. The African cichlid fish Astatotilapia burtoni uses multimodal communication in social contexts such as courtship, territoriality, and parental care and shows plasticity in sensory abilities. In this review, we synthesize what is known about how visual, acoustic, and chemosensory communication is used in A. burtoni in inter- and intra-specific social contexts, how sensory funtion is modulated by an individual's reproductive, metabolic, and social state, and discuss evidence for plasticity in potential modulators that may contribute to changes in sensory abilities and behaviors. Sensory plasticity in females is primarily associated with the natural reproductive cycle and functions to improve detection of courtship signals (visual, auditory, chemosensory, and likely mechanosensory) from high-quality males for reproduction. Plasticity in male sensory abilities seems to function in altering their ability to detect the status of other males in the service of territory ownership and future reproductive opportunities. Changes in different classes of potential modulators or their receptors (steroids, neuropeptides, and biogenic amines) occur at both peripheral sensory organs (eye, inner ear, and olfactory epithelium) and central visual, olfactory, and auditory processing regions, suggesting complex mechanisms contributing to plasticity of sensory function. This type of sensory plasticity revealed in males and females of A. burtoni is likely more widespread among diverse animals than currently realized, and future studies should take an integrative and comparative approach to better understand the proximate and ultimate mechanisms modulating communication abilities across taxa.

Circadian fluctuations in glucocorticoid level predict perceptual discrimination sensitivity

Slow neurobiological rhythms, such as the circadian secretion of glucocorticoid (GC) hormones, modulate a variety of body functions. Whether and how endocrine fluctuations also exert an influence on perceptual abilities is largely uncharted. Here, we show that phasic increases in GC availability prove beneficial to auditory discrimination. In an age-varying sample of N = 68 healthy human participants, we characterize the covariation of saliva cortisol with perceptual sensitivity in an auditory pitch discrimination task at five time points across the sleep-wake cycle. First, momentary saliva cortisol levels were captured well by the time relative to wake-up and overall sleep duration. Second, within individuals, higher cortisol levels just prior to behavioral testing predicted better pitch discrimination ability, expressed as a steepened psychometric curve. This effect of GCs held under a set of statistical controls. Our results pave the way for more in-depth studies on neuroendocrinological determinants of sensory encoding and perception.

Assessment of otolith function using vestibular evoked myogenic potential in women during pregnancy

Introduction

More than 50% of pregnant women experience dizziness frequently in the first two gestational trimesters. During pregnancy, the changes in the metabolism of hormones are responsible for the ovarian cycle resulting in either peripheral or central vestibular alterations. The need for the study is to focus on the effect of changes during pregnancy on the vestibular evoked myogenic potential, an electrophysiological measure that investigates functions of the otolith structures.

Objectives

The aim is to investigate the vestibular evoked myogenic potential responses during the first trimester of pregnancy.

Methods

A total of 17 pregnant women and 17 non-pregnant women with age matched took part in this study. The cervical vestibular evoked myogenic potential were recorded from the ipsilateral sternocleridomastoid muscle and the ocular vestibular evoked myogenic potential were recorded from contralateral extraocular muscle in both groups.

Results

Peak to peak amplitude of cervical vestibular evoked myogenic potential and ocular vestibular evoked myogenic potential was found to be significantly reduced in the responses obtained from first-trimester pregnant women when compared to that of non-pregnant women.

Conclusions

Vestibular evoked myogenic potential tests exhibits a clinically significant reduced peak to peak amplitude in the first trimester of pregnancy, which indicates dysfunction in the otolith reflex pathway.

Stool frequency and form and gastrointestinal symptoms differ by day of the menstrual cycle in healthy adult women taking oral contraceptives: a prospective observational study

Background

Little is known about how the menstrual cycle affects gastrointestinal function and self-reported stress in young, healthy women taking oral contraceptives (OC). This study prospectively characterized gastrointestinal function and symptoms on each day throughout the menstrual cycle.

Methods

Healthy women aged 18–35 years (n = 78) who took OC participated in the 5-week observational study. Stool frequency, self-reported stress, stool form measured by the Bristol Stool Form Scale (BSFS), and gastrointestinal symptoms measured by a modified version of the Gastrointestinal Symptom Rating Scale (GSRS) were assessed daily. GSRS scores were reported (1 = no discomfort at all, 7 = very severe discomfort) and were averaged for individual syndrome scores or summed for the total score. The validated, weekly version of the GSRS was completed at two time points to reflect menstruation and 1 week prior to menstruation (n = 72). Outcomes were analyzed in linear mixed models with the Dunnett’s post hoc test against day 1 of menstrual bleeding or with nonparametric tests.

Results

Daily stress (P = 0.0018), BSFS score (P = 0.0493), stool frequency (P = 0.0241), abdominal pain (P < 0.0001), diarrhea (P = 0.0022), constipation (P = 0.0446), reflux (P = 0.0193), and indigestion (P < 0.0001) all varied significantly by the day of the menstrual cycle. Dunnett’s post hoc tests showed that scores (mean ± SEM) on the first day of bleeding (day 1) for daily abdominal pain (2.6 ± 0.2), diarrhea (1.7 ± 0.1), and indigestion (2.1 ± 0.2) symptoms were higher than scores on all other days of the menstrual cycle (P < 0.05) with scores not on day 1 falling under 1.5, or between no discomfort at all and slight discomfort. Reflux, stool frequency, BSFS, self-reported stress, and constipation were higher on day 1 (P < 0.05) than on 12, 8, 6, 4, and 2 other days of the menstrual cycle, respectively. The median (IQR) GSRS score was higher during the week of menstruation than the week prior to menstruation for diarrhea [1.50 (1.00–2.33) vs 1.33 (1.00–2.00), P = 0.002] and abdominal pain [2.00 (1.33–2.67) vs 1.67 (1.33–2.33), P = 0.011] syndrome scores.

Conclusion

Bowel habits appear to vary across the menstrual cycle and suggest more gastrointestinal discomfort on day 1 of menstrual bleeding in healthy women taking OC. Future interventional studies could identify ways to improve gastrointestinal symptoms in healthy women during menstruation.

The Prevalence of Hearing, Vision, and Dual Sensory Loss in Older Canadians: An Analysis of Data from the Canadian Longitudinal Study on Aging

The purpose of this study was to describe the prevalence of hearing loss (HL), vision loss (VL), and dual sensory loss (DSL) in Canadians 45–85 years of age. Audiometry and visual acuity were measured. Various levels of impairment severity were described. Results were extrapolated to the 2016 Canadian population. In 2016, 1,500,000 Canadian males 45–85 years of age had at least mild HL, 1,800,000 had at least mild VL, and 570,000 had DSL. Among females, 1,200,000 had at least mild HL, 2,200,000 had at least mild VL, and 450,000 had DSL. Among Canadians 45–85 years of age, mild, moderate, and severe HL was prevalent among 13.4 per cent, 3.7 per cent, and 0.4 per cent of males, and among 11.3 per cent, 2.3 per cent, and 0.2 per cent of females, respectively. Mild and moderate, or severe VL was prevalent among 19.8 per cent and 2.4 per cent of males, and among 23.9 per cent and 2.6 per cent of females, respectively. At least mild DSL was prevalent among 6.4 per cent of males and 6.1 per cent of females.

Separate auditory pathways for the induction and maintenance of tinnitus and hyperacusis?

Tinnitus and hyperacusis often occur together, however tinnitus may occur without hyperacusis or hyperacusis without tinnitus. Based on animal research one could argue that hyperacusis results from noise exposures that increase central gain in the lemniscal, tonotopically organized, pathways, whereas tinnitus requires increased burst firing and neural synchrony in the extra-lemniscal pathway. However, these substrates are not sufficient and require involvement of the central nervous system. The dominant factors in changing cortical networks in tinnitus patients are foremost the degree and type of hearing loss, and comorbidities such as distress and mood. So far, no definite changes have been established for tinnitus proper, albeit that changes in connectivity between the dorsal attention network and the parahippocampal area, as well as the default-mode network-precuneus decoupling, appear to be strong candidates. I conclude that there is still a strong need for further integrating animal and human research into tinnitus and hyperacusis.

Understanding hormone and hormone therapies' impact on the auditory system

Hormones such as estrogen, progesterone, and aldosterone all demonstrate vital roles in sustaining auditory function through either the maintenance of cochlear neurons, up/down regulation of critical molecules (i.e., IGF-1, BDNF, etc.), or generation of the endocochlear potential. With disease and/or age, hormone expression begins to decline drastically, which ultimately affects cochlear structures and the integrity of cochlear cells. The following review explores the latest findings as well as realistic outcomes for hormone therapy treatment in the auditory system. This information could serve as a potential guide for patients considering hormone therapy as a medicinal choice to alleviate the signs of onset of presbycusis-age-related hearing loss. Additional scientific investigations could also be carried out to further enhance recent findings.

Mouse methods and models for studies in hearing

Laboratory mice have become the dominant animal model for hearing research. The mouse cochlea operates according to standard "mammalian" principles, uses the same cochlear cell types, and exhibits the same types of injury as found in other mammals. The typical mouse lifespan is less than 3 years, yet the age-associated pathologies that may be found are quite similar to longer-lived mammals. All Schuknecht's types of presbycusis have been identified in existing mouse lines, some favoring hair cell loss while others favor strial degeneration. Although noise exposure generally affects the mouse cochlea in a manner similar to other mammals, mice appear more prone to permanent alterations to hair cells or the organ of Corti than to hair cell loss. Therapeutic compounds may be applied systemically or locally through the tympanic membrane or onto (or through) the round window membrane. The thinness of the mouse cochlear capsule and annular ligament may promote drug entry from the middle ear, although an extremely active middle ear lining may quickly remove most drugs. Preclinical testing of any therapeutic will always require tests in multiple animal models. Mice constitute one model providing supporting evidence for any therapeutic, while genetically engineered mice can test hypotheses about mechanisms.

The effect of premature ovarian failure on inner ear function

The aim of this study was to test whether hearing function is impaired in women with premature ovarian failure. Thirty (30) women with premature ovarian failure (POF), 30 women in menopause and 30 healthy controls were recruited in this study. Pure tone audiometric (PTA), transiently evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) of the study participants were analysed. At PTA, 6 and 8 kHz were lower in menopause group compared with both women with POF and controls. At TEOAE 3 and 4 kHz and at DPOAE 1, 2, 4 and 6 kHz were lower in menopause group compared with the controls. At DPOAE 6 kHz was lower in the POF group compared with the controls. Women with POF comparing to menopause group at TEOAE 3, 4 kHz and at DPOAE 4 and 6 kHz were lower in the menopause group. Inner ear function of both women in menopause and women with POF was declined compared to the healthy controls. Clinically, evaluation of hearing status may be considered in women with POF.Impact statementWhat is already known on this subject: Premature ovarian failure (POF) affects 1%-2% of women, and it adversely effects on health status (such as cardiovascular, psychological and cognitive disorders). Previous studies suggested that a lack of oestrogen might play a role in hearing disorders in women. However, we do not know POF's adversely effect on cochlea and hearing.What the results of this study add: The present study demonstrates that lower serum oestrogen has a negative effect hearing in women with POF at DPOAE 6 kHz.What the implications are of these findings for clinical practice and/or further research: The women with POF must be evaluated for hearing status.

Pregnancy Does Not Increase the Risk of Sudden Sensorineural Hearing Loss: A National Cohort Study

OBJECTIVES/HYPOTHESIS

Pregnancy-induced systemic physiological changes appear to be associated with reversible hearing changes in pregnant/postpartum women. However, most studies are case reports due to the rare occurrence of sudden sensorineural hearing loss (SSNHL) during pregnancy. We aimed to evaluate the risk of SSNHL during the pregnancy and postpartum periods.

STUDY DESIGN

A longitudinal case-control study using a nationwide population cohort.

METHODS

Using the Korean National Health Insurance Review and Assessment Service, we collected data from 63,331 pregnant/postpartum participants who were matched 1:2 by age, income, region of residence, and medical history with 126,662 control participants. We included participants who had International Classification of Diseases, 10th Revision (ICD-10) codes indicating delivery (O80-O84). For SSNHL (ICD-10 code H91.2), we included only those participants who underwent audiometry and were treated with steroids. The incidence of SSNHL was measured for the periods corresponding to pregnancy (conception through delivery) up to 1 year postpartum in the pregnant participants.

RESULTS

During the pregnancy period, the SSNHL rate was not higher (19.5 per 100,000) compared with the control group (60.7 per 100,000). The adjusted odds ratio of SSNHL during pregnancy was 0.32 (95% confidence interval: 0.16-0.65, P = .002). The SSNHL rate during the postpartum period (37.9 per 100,000) was similar to that of the control group (36.3 per 100,000). The adjusted odds ratio of SSNHL during the postpartum period was 1.04 (95% confidence interval: 0.64-1.71, P = .867). The risk of SSNHL in the patients during the pregnancy/postpartum period was not higher than that in controls, regardless of age and specific subperiod.

CONCLUSIONS

The pregnant and postpartum women were not at higher risk of SSNHL.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:E237-E242, 2020.

Environmental ototoxicants, a potential new class of chemical stressors

Hearing loss is an injury that can develop over time, and people may not even be aware of it until it becomes a severe disability. Ototoxicants are substances that may damage the inner ear by either affecting the structures in the ear itself or by affecting the nervous system. We have examined the possibility that ototoxicants may present a health hazard in association with environmental exposures, adding to existing knowledge of their proven hazards under medical therapeutic conditions or occupational activities. In addition to the already described human environmental ototoxicants, mainly organochlorines such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), hexachlorocyclohexane (HCH) and hexachlorobenzene (HCB), we have examined the ubiquitous chemical stressors phthalates, bisphenol A/S/F/, PFCs, flame retardants (FRs) and cadmium for potential ototoxic properties, both as single substances or as chemical mixtures. Our literature review confirmed that these chemicals may disturb thyroid hormones homeostasis, activate aryl hydrocarbon receptor (AhR), and induce oxidative stress, which in turn may initiate a chain of events resulting in impairment of cochlea and hearing loss. With regard to auditory plasticity, diagnostics of a mixture of effects of ototoxicants, potential interactions of chemical and physical agents with effects on hearing, parallel deterioration of hearing due to chemical exposures and ageing, metabolic diseases or obesity, even using specific methods as brainstem auditory evoked potentials (BAEP) or otoacoustic emissions (OAEs) registration, may be difficult, and establishment of concentration-response relationships problematic. This paper suggests the establishment of a class of environmental oxotoxicants next to the established classes of occupational and drug ototoxicants. This will help to properly manage risks associated with human exposure to chemical stressors with ototoxic properties and adequate regulatory measures.

Male dominance status regulates odor-evoked processing in the forebrain of a cichlid fish

The ability to identify odors in the environment is crucial for survival and reproduction. However, whether olfactory processing in higher-order brain centers is influenced by an animal's physiological condition is unknown. We used in vivo neuron and local field potential (LFP) recordings from the ventral telencephalon of dominant and subordinate male cichlids to test the hypothesis that response properties of olfactory neurons differ with social status. Dominant males had a high percentage of neurons that responded to several odor types, suggesting broad tuning or differential sensitivity when males are reproductively active and defending a territory. A greater percentage of neurons in dominant males also responded to sex- and food-related odors, while a greater percentage of neurons in subordinate males responded to complex odors collected from behaving dominant males, possibly as a mechanism to mediate social suppression and allow subordinates to identify opportunities to rise in rank. Odor-evoked LFP spectral densities, indicative of synaptic inputs, were also 2-3-fold greater in dominant males, demonstrating status-dependent differences in processing possibly linking olfactory and other neural inputs to goal-directed behaviors. For the first time we reveal social and reproductive-state plasticity in olfactory processing neurons in the vertebrate forebrain that are associated with status-specific lifestyles.

The effect of the menstrual cycle on dichotic listening

The purpose of this study was to determine the effect of the menstrual cycle on responses to a dichotic listening task. It was hypothesized that participants would exhibit a stronger right ear advantage during the menstrual cycle days when estrogen levels are at their peak. It was also hypothesized that the women not taking oral contraceptives would exhibit greater variations in ear advantage over the course of their menstrual cycle than those taking oral contraceptives. Finally, it was hypothesized that the error response rates would remain similar across different listening conditions and over the menstrual cycle. The participants were 30 women who took oral contraceptives and 15 who did not. They completed nine listening sessions comprised of three dichotic listening tasks: forced-left, forced-right, and open. The data were analyzed using a mixed effects models. The participants exhibited a reduction in right ear responses on the days that corresponded to when the level of estrogen would begin to increase. This response was different from what had been hypothesized. The analysis also indicated no response differences between the two groups of women. In addition, the women exhibited fewer errors over the course of the sessions, implying that they adapted to the task. The results indicate that the women’s hormone fluctuation across the menstrual cycle affected their responses to the forced-left, cognitive control, task only.

Pilot study on patients with Mal de Debarquement syndrome during pregnancy

Aim:

To evaluate if patients with Mal de Debarquement syndrome (MdDS) demonstrate different symptom levels or symptom type during pregnancy.

Materials & methods:

18 MdDS patients that were or had been pregnant during their condition were recruited to complete a retrospective online questionnaire. Respondents answered questions regarding their basic clinical data, diagnosis, triggers and differences in symptom level and symptom type during pregnancy and before pregnancy.

Results:

A total of 81.3% reported that their symptoms were reduced during pregnancy compared with before pregnancy. Respondents also reported a different perception of motion and experienced less dizziness while being pregnant.

Conclusion:

The physiological changes that occur during pregnancy improve the symptoms of patients with MdDS, and this is potentially attributable to the rise in estrogen and progesterone.

Mal de Debarquement syndrome (MdDS) is a rare neurological disorder characterized by a constant sensation of self-motion. More women are affected than men, and subsequently a hormonal implication has been theorized. This study aimed to evaluate if symptoms change in patients with MdDS during their pregnancy. A total of 18 MdDS patients were recruited to complete a retrospective online questionnaire. Among these, 81.3% of respondents reported that their symptoms were lower during pregnancy compared with before pregnancy. Respondents also reported a different perception of motion and experienced less dizziness while being pregnant. Our results support the hypothesis that pregnancy positively influences MdDS symptoms.

Neuroprotective factors and incident hearing impairment in the epidemiology of hearing loss study

OBJECTIVE

Hearing impairment (HI) is common in aging adults. Aldosterone, insulin-like growth factor (IGF1), and brain-derived neurotrophic factor (BDNF) have been identified as potentially protective of hearing. The present study aims to investigate these relationships.

METHODS

The Epidemiology of Hearing Loss Study is a longitudinal population-based study of aging in Beaver Dam, Wisconsin, that began in 1993. Baseline for the present investigation is the 1998 to 2000 phase. Follow-up exams occurred approximately every 5 years, with the most recent occurring from 2013 to 2016. Hearing was measured by pure-tone audiometry. HI was defined as a pure tone average (PTA) > 25 decibels hearing level in either ear. Change in PTA was the difference between follow-up examinations and baseline. Baseline serum samples were used to measure biomarkers in 2017. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated to assess the effect of biomarker levels in the lowest quintile (Q1) versus the highest (Q5) on incident HI and PTA change.

RESULTS

There were 1,088 participants (69.3% women) at risk of HI included in analyses. The mean baseline age was 63.8 years (standard deviation = 7.0). The 16-year incidence of HI was 54.9% and was higher in men (61.1%) than women (52.1%). In age- and sex-adjusted models, aldosterone (HR = 1.06, 95% CI = 0.82-1.37), IGF1 (HR = 0.92, 95% CI = 0.71-1.19), and BDNF (HR = 0.86, 95% CI = 0.66-1.12) levels were not associated with risk of HI. PTA change was similarly not affected by biomarker levels.

CONCLUSION

Aldosterone, IGF1, and BDNF were not associated with decreased risk of age-related hearing loss in this study.

LEVEL OF EVIDENCE

2b Laryngoscope, 129:2178-2183, 2019.

Hearing Performance in the Follicular-Luteal Phase of the Menstrual Cycle

Introduction

Estrogen has a protective role on auditory function. It may have an excitatory action on auditory nerve fibers and can have a neuroprotective effect. Progesterone has a mainly inhibitory action on the central nervous system, which may balance the mainly excitatory action of estrogen.

Objective

To determine changes in hearing performance with pure tone audiometry (PTA), tympanometry, distortion product otoacoustic emissions (DPOAEs), and auditory brainstem responses (ABR) as hormonal changes occur from follicular to luteal phase.

Materials and Methods

Twenty healthy female volunteers (age 19 ± 30 years) with normal menstrual cycle and without any hearing problems are included in this case-control study. Hearing evaluation was performed on the 13th day of the menstrual cycle (follicular phase) and then on the 22nd day (luteal phase).

Results

All of the participants had normal results in follicular phase. In luteal phase, four cases showed abnormalities as follows: reduced hearing thresholds 250 Hz (mean= 15 dBHL), increased amplitudes of DPOAE (mean= 3 dBspl), decreased middle ear pressure (mean= -110 dapa), and delayed ABR interpeak latencies (mean of IPLs I-III= 0.4 and mean of IPLs III-V= 0.6 ms).

Conclusions

In some women, changing of ovarian hormones may induce fluctuating hearing and increased progesterone in luteal phase can lead to abnormal outcomes in auditory function. However, elevated estrogen modifies its consequences in follicular phase.

Astatotilapia burtoni: A Model System for Analyzing the Neurobiology of Behavior

Most biomedical research is performed using a very limited number of "model" species. In part, this has resulted from a combination of full genomes, manipulation of genes, and short generation times in these species. However, the advent of low-cost sequencing and gene editing in any organism has increased the use of nontraditional organisms. Many scientists have paraphrased the adage by Krogh [ Krogh , A. ( 2018 ) Science 70 , 200 - 204 ] that for many biological problems some species will prove to be most convenient and useful to study. In particular, using organisms most suited to the specific research question can lead to novel insights about fundamental physiological, neurobiological, immunological, and neuroendocrine systems that can advance our understanding of the well-being and health of humans. In addition, such studies have led to new ideas about the evolution and mechanisms that control social behavior. Fishes constitute about 50% of all vertebrate species and are the most diverse vertebrate radiation. Here we review behavioral and neurobiological discoveries of plasticity in social behavior resulting from analysis of an African cichlid fish, showing how its unique behavioral system has facilitated a broad range of discoveries. For many future questions, Astatotilapia burtoni and other cichlid fishes may be ideally suited to study as we advance our understanding of the neural basis of social decisions.

Bidirectional associations between psychological distress and hearing problems: an 18-year longitudinal analysis of the British Household Panel Survey

OBJECTIVE

Hearing problems are a significant public health concern. It has been suggested that psychological distress may represent both a cause and a consequence of hearing problems. Prospective data that allow testing such potential bi-directionality have thus far been lacking. The present study aimed to address this knowledge gap. Random (RE) and fixed effects (FE) panel regression models estimated the association of psychological distress (GHQ-12) and participant-reported hearing problems. Data from 18 annual waves of the British Household Panel Survey were used (n = 10,008). Psychological distress was prospectively associated with self-reported hearing problems in women (multivariable odds ratios (ORs) ≥1.44; one-year time lag ≥ 1.16) and men (ORs ≥ 1.15; time lag ≥ 1.17). Conversely, self-reported hearing problems were associated with increases in psychological distress in both sexes (OR ≥ 1.26; time lag ≥ 1.08). These associations were independent of the analytical strategy and of adjustment for sociodemographic variables, lifestyle factors, and measurement period. We present first evidence of a bidirectional association between psychological distress and self-reported hearing problems. These findings suggest that stress management interventions may contribute to the prevention of self-reported hearing problems, and, in turn, alleviating self-reported hearing problems may reduce psychological distress.

Mal de Debarquement Syndrome: A Retrospective Online Questionnaire on the Influences of Gonadal Hormones in Relation to Onset and Symptom Fluctuation

Introduction

Mal de Debarquement Syndrome (MdDS) is a condition characterized by a persistent perception of self-motion, in most cases triggered from exposure to passive motion (e.g., boat travel, a car ride, flights). Patients whose onset was triggered in this way are categorized as Motion-Triggered (MT) subtype or onset group. However, the same syndrome can occur spontaneously or after non-motion events, such as childbirth, high stress, surgery, etc. Patients who were triggered in this way are categorized as being of the Spontaneous/Other (SO) subtype or onset group. The underlying pathophysiology of MdDS is unknown and there has been some speculation that the two onset groups are separate entities. However, despite the differences in onset between the subtypes, symptoms are parallel and a significant female predominance has been shown. To date, the role of gonadal hormones in MdDS pathophysiology has not been investigated. This study aimed to evaluate the hormonal profile of MdDS patients, the presence of hormonal conditions, the influence of hormones on symptomatology and to assess possible hormonal differences between onset groups. In addition, the prevalence of migraine and motion sickness and their relation to MdDS were assessed.

Method

Retrospective online surveys were performed in 370 MdDS patients from both onset groups. Data were analyzed using Fisher’s exact test or Fisher-Freeman-Hanlon exact test. When possible, data were compared with normative statistical data from the wider literature.

Results

From the data collected, it was evident that naturally cycling female respondents from the MT group were significantly more likely to report an aggravation of MdDS symptoms during menses and mid-cycle (p < 0.001). A few preliminary differences between the onset groups were highlighted such as in regular menstrual cycling (p = 0.028), reporting menses during onset (p < 0.016), and migraine susceptibility after onset (p = 0.044).

Conclusion

These results demonstrate a potential relation between hormone fluctuations and symptom aggravation in the MT group. This study is an important first step to suggest a hormonal involvement in the pathophysiology of MdDS and provides a base for further hormonal investigation. Future prospective studies should expand upon these results and explore the implications for treatment.

Hormone replacement therapy decreases the risk of tinnitus in menopausal women: a nationwide study

The incidence and risk of tinnitus associated with hormone replacement therapy (HRT) in menopausal women have not yet been fully examined. We examined the medical records of menopausal women aged between 45 and 79 years from Taiwan's National Health Insurance Research Database of records between 1 January 2000 and 31 December 2010 to establish matched cohorts (13,920 HRT users and 41,760 nonusers). The incidence of tinnitus in HRT users and nonusers were matched 1:3 based on propensity-score matching over this ten year period. The Cox regression hazard model was used to identify risk factors of tinnitus, and results indicate that a significantly lower percentage of HRT users (P = 0.017) developed tinnitus in comparison with nonusers (0.43%, 60/13, 920 vs. 0.59%, 246/41, 760). Using Cox regressions analysis after adjustments for age and other variables (adjusted hazard ratio: 0.505 (95% confidence interval, 0.342–0.756)), we were also able to show that HRT users appeared to have a reduced risk of developing tinnitus in comparison with nonusers. Based on our observation of the lower incidence of tinnitus among HRT users in this cohort, we speculate that HRT may have provided potential benefits on the management and prevention of tinnitus among menopausal women.

Effects of combined oral contraception containing drospirenone on premenstrual exacerbation of Meniere's disease: Preliminary study

OBJECTIVES

Meniere's disease is caused by an augmented endolymph pressure in the inner ear; symptoms are vertigo, fluctuating hearing loss and tinnitus. Exacerbations has been noted during premenstrual phase. The study aims to evaluate the effects of a 20 μm Ethinylestradiol (EE) and 3 mg Drospirenone (DRSP) oral contraceptive (20 μmEE/3mgDRSP) in continuous regimen, associated with rehabilitation therapy on Meniere's disease.

STUDY DESIGN

This non-randomized controlled study was performed from October 2015 to October 2017. Forty-two premenopausal women affected by MD with severe distress in the premenstrual phase were enrolled. Sixteen women constituted the study group (Group A), and twenty women constituted the control group (Group B). Group A underwent EE/DRSP therapy and rehabilitation and Group B underwent rehabilitation therapy alone. Stabilometry and the Dizziness Handicap Inventory questionnaire were used to measure vestibular function and distress related to the disease, respectively, at baseline (T0), 3 months (T1) and 6 months (T2).

RESULTS

At T0, both groups had large, similar areas of stabilometric ellipses (p = NS) that reduced more in Group A than in Group B, at T1 and T2 (p < 0.001). High scores of the DHI (cut-off ≤54) were observed at T0 in both groups (A 66.8 ± 2.8 vs B 65.5 ± 3.6; p = NS). At T1, a gradual improvement in both groups was observed, manly in Group A (A 45.1 ± 3.6 vs B 62.4 ± 4.1; p < 0.001). At T2, the DHI scores were significantly lower in Group A (39.2 ± 3.8) compared to Group B (68.8 ± 3.6) (p < 0.001).

CONCLUSIONS

DRSP could be effective in reducing the fluid overload typical of the premenstrual phase, improving symptoms of MD. The results support the efficacy of EE/DRSP usage associated with rehabilitation therapy on premenstrual exacerbation of MD.

Variation in the Hearing Threshold in Women during the Menstrual Cycle

Introduction  The hormonal changes that occur during the menstrual cycle and their relationship with hearing problems have been studied. However, they have not been well explained. Objective  The objective of our study is to investigate the variation in hearing thresholds in women during the menstrual cycle. Method  We conducted a cohort and longitudinal study. It was composed of 30 volunteers, aged 18-39 years old, of which 20 were women during the phases of the menstrual cycle and 10 were men (control group) who underwent audiometry and impedance exams, to correlate the possible audiological changes in each phase of the menstrual cycle. Results  There were significant changes in hearing thresholds observed during the menstrual cycle phases in the group of women who used hormonal contraceptives and the group who did not use such contraceptives. Improved hearing thresholds were observed in the late follicular phase in the group who did not use hormonal contraceptives and the hearing thresholds at high frequencies were better. Throughout the menstrual cycle phases, the mean variation was 3.6 db HL between weeks in the group who used hormonal contraceptives and 4.09 db HL in the group who did not use them. Conclusions  The present study found that there may be a relationship between hearing changes and hormonal fluctuations during the menstrual cycle based on changes in the hearing thresholds of women. In addition, this study suggests that estrogen has an otoprotective effect on hearing, since the best hearing thresholds were found when estrogen was at its maximum peak.

Association Between Sex and Speech Auditory Brainstem Responses in Adults, and Relationship to Sex Hormone Levels

BACKGROUND The aim of this study was to investigate the association between sex and speech-ABR in adults, and its relationship to sex hormone levels. MATERIAL AND METHODS Speech-ABR were elicited with the consonant-vowel syllable (/da/) in a total of 35 adults. Reproductive hormone levels were also measured. RESULTS The transient response of the speech-ABR (waves V, A, and O) in females show a shorter latency (waves V, A and O) and a larger amplitude (waves V and A) than in males (P<0.05), except for the amplitude of peak O (P>0.05). The sustained response of females exhibited a larger amplitude (wave F, P<0.05) and a shorter latency (wave D, E, and F, P<0.05) than in males, except for the amplitude of peak D and E (P>0.05). The latencies of speech-ABR were positively correlated with testosterone level (P<0.05), and were negatively correlated with estradiol (E2) levels (P<0.05), except for wave E (P>0.05). The E2 showed a positive correlation with the absolute value of amplitude of the speech-ABR (P < 0.05). On the contrary, total testosterone showed a negative correlation with the absolute value of amplitude the speech-ABR (P<0.05), except for wave D and wave O (P>0.05). CONCLUSIONS Sex differences in speech-ABR are significant in adults. The latencies and amplitude of the speech-ABR waves were correlated with the E2 concentration and testosterone level. The sex hormones likely affect speech encoding in the brainstem.

Clinical Study on 136 Children with Sudden Sensorineural Hearing Loss

Background:

The prevalence of sudden sensorineural hearing loss in children (CSSNHL) is consistently increasing. However, the pathology and prognosis of CSSNHL are still poorly understood. This retrospective study evaluated clinical characteristics and possible associated factors of CSSNHL.

Methods:

One hundred and thirty-six CSSNHL patients treated in Department of Otolaryngology-Head and Neck Surgery and Institute of Otolaryngology at Chinese PLA General Hospital between July 2008 and August 2015 were included in this study. These patients were analyzed for clinical characteristics, audiological characteristics, laboratory examinations, and prognostic factors.

Results:

Among the 136 patients (151 ears), 121 patients (121 ears, 80.1%) were diagnosed with unilaterally CSSNHL, and 15 patients (30 ears, 19.9%) with bilateral CSSNHL. The complete recovery rate of CSSNHL was 9.3%, and the overall recovery rate was 37.7%. We found that initial degree of hearing loss, onset of treatment, tinnitus, the ascending type audiogram, gender, side of hearing loss, the recorded auditory brainstem response (ABR), and distortion product otoacoustic emissions (DPOAEs) had prognostic significance. Age, ear fullness, and vertigo had no significant correlation with recovery. Furthermore, the relevant blood tests showed 30.8% of the children had abnormal white blood cell (WBC) counts, 22.1% had elevated homocysteine levels, 65.8% had high alkaline phosphatase (ALP), 33.8% had high IgE antibody levels, and 86.1% had positive cytomegalovirus (CMV) IgG antibodies.

Conclusions:

CSSNHL commonly occurs unilaterally and results in severe hearing loss. Initial severe hearing loss and bilateral hearing loss are negative prognostic factors for hearing recovery, while positive prognostic factors include tinnitus, gender, the ascending type audiogram, early treatment, identifiable ABR waves, and DPOAEs. Age, vertigo, and ear fullness are not correlated with the recovery. Some serologic indicators, including the level of WBC, platelet, homocysteine, ALP, positive CMV IgG antibody, fibrinogen, and some immunologic indicators, are closely related to CSSNHL.

Application of Mouse Models to Research in Hearing and Balance

Laboratory mice (Mus musculus) have become the major model species for inner ear research. The major uses of mice include gene discovery, characterization, and confirmation. Every application of mice is founded on assumptions about what mice represent and how the information gained may be generalized. A host of successes support the continued use of mice to understand hearing and balance. Depending on the research question, however, some mouse models and research designs will be more appropriate than others. Here, we recount some of the history and successes of the use of mice in hearing and vestibular studies and offer guidelines to those considering how to apply mouse models.

DPOAEs in infants developmentally exposed to PCBs show two differently time spaced exposure sensitive windows

The study aim was to identify the timing of sensitive windows for ototoxicity related to perinatal exposure to PCBs. A total of 351 and 214 children from a birth cohort in eastern Slovakia underwent otoacoustic testing at 45 and 72 months, respectively, and distortion product otoacoustic emissions (DPOAEs) at 11 frequencies were recorded. Cord and child 6-, 16-, 45-, and 72- month blood samples were analyzed for PCB 153 concentration. The PCB 153 concentration-time profiles were approximated with a system model to calculate area under the PCB*time curves (AUCs) for specific time intervals (3 and 6 months for 45 and 72 months data, respectively). DPOAE amplitudes were correlated (Spearman) with cord serum PCB and AUCs, markers of prenatal and postnatal exposure, respectively. Two exposure critical windows were identified in infants, the first related to prenatal and early postnatal and the second to postnatal exposure to PCBs. Our data have shown tonotopicity, sexual dimorphism, and asymmetry in ototoxicity of PCBs.

Influence of Hormonal Changes on Audiologic Examination in Normal Ovarian Cycle Females: An Analytic Study

Introduction There is only limited information from previous studies that suggest that auditory function may be influenced by hormones. Recent advances in the field have exposed the potential role of hormones in modulating the auditory system. Objective This study aims to investigate the relationship between menstrual cycle and outer hair cell function with audiological examination. Methods This is an analytic study with a cross-sectional design. The sampling was a systematic random sampling. We found 49 women with normal menstrual cycle and collected their data through interviews, physical examination, and examination of the ear, with otoscopic and other routine otorhinolaryngology examinations. We evaluated Tympanometry, distortion-product otoacoustic emissions (DPOAE), and pure tone audiometry. Results We found the audiometric threshold worse in the follicular phase than other phases at 4000 Hz of the right ear, and in the ovulation was found best than any other phases at 1000 Hz of the left ear with significant difference. We found significant difference of DPOAE between ovulation time and follicular phase at 3000 Hz and 1000 Hz in the left ear and between ovulation and luteal phased at 2000 Hz, 3000 Hz and 5000 Hz in the right ear and at 1000 Hz in the left ear with p < 0.05. Conclusion The result of this study showed that only a small part of audiometry threshold had a significant difference between each menstrual phase. In other words, we found no correlation between menstrual and audiometry threshold. Nonetheless, there is a correlation between menstrual cycle phase and DPOAE amplitude.

The acute physiological stress response to an emergency alarm and mobilization during the day and at night

The purpose of this study was to investigate the acute physiological stress response to an emergency alarm and mobilization during the day and at night. Sixteen healthy males aged 25 ± 4 years (mean ± SD) spent four consecutive days and nights in a sleep laboratory. This research used a within-participants design with repeated measures for time, alarm condition (alarm or control), and trial (day or night). When an alarm sounded, participants were required to mobilize immediately. Saliva samples for cortisol analysis were collected 0 min, 15 min, 30 min, 45 min, 60 min, 90 min, and 120 min after mobilization, and at corresponding times in control conditions. Heart rate was measured continuously throughout the study. Heart rate was higher in the day (F(20,442) = 9.140, P < 0.001) and night (F(23,459) = 8.356, P < 0.001) alarm conditions compared to the respective control conditions. There was no difference in saliva cortisol between day alarm and day control conditions. Cortisol was higher (F(6,183) = 2.450, P < 0.001) following the night alarm and mobilization compared to the night control condition. The magnitude of difference in cortisol between night control and night alarm conditions was greater (F(6,174) = 4.071, P < 0.001) than the magnitude of difference between the day control and day alarm conditions. The augmented heart rate response to the day and night alarms supports previous observations in field settings. Variations in the cortisol responses between conditions across the day and night may relate to differences in participants' ability to interpret the alarm when sleeping versus when awake.